Hey mommy's I need some help. I got the birth control that you get in your arm that is good for 3…

Hey mommy's I need some help. I got the birth control that you get in your arm that is good for 3 years. I got it 5/25/2016. I had my daughter January 12th and I had my gallbladder removed may 12th 2016. And here it is 8 month later and I still will bleed. Does anyone know why that is because everyone I talk to that has it says there periods stop? Please help me